8, the "seminal work that Britten felt to be 'my Op. 1 all right.'" Auden selected the subject of "man's relation to animals," chose three old poems dealing with a plague of rats, the death of a pet monkey, and hunting partridges, and wrote a prologue and epilogue. The material was undoubtedly difficult to set but Auden, whose own additions were "criticised as unduly obscure," proceeded on the belief that "what composers responded to were not so much clear-cut sentences as rhythmically stressed syllables and carefully placed keywords." Britten meaningfully counterpointed the highlighted points in Auden's rhythmic design and enriched the sense of the lines by carefully placed emphases. Britten's high regard for this work indicates that he was "acutely aware of Auden's agency in releasing for the first time his full powers."
In 1937 Britten composed his Variations on a Theme of Frank Bridge op. 10 which, when it was performed at the Salzburg Festival that year, "established Britten's international reputation." His next major work was his first song cycle, On this Island op. 11, for which he chose to set five lyrics by Auden. This work "was the product of two young minds thinking along related lines and working to a common purpose" and its success spurred further collaboration. The pair did further important work that displayed the range of which they were capable--from the "glitzy insouciance" of their Cabaret Songs (1938) to the bitterness of the Ballad of Heroes (1939), written for those who fell in the Spanish Civil War. Thus when Auden and the novelist Christopher Isherwood emigrated to the United States in 1939 Britten and the great singer Peter Pears, his lifetime companion, followed in April 1939. Three years in America saw the production of some of Britten's "undisputed masterpieces," such as Sinfonia da Requiem op. 20 and Seven Sonnets of Michelangelo op. 22 and, eager to make themselves at home in their new c...